He said up to 1,000 training slots will be offered this year in more specialised areas such as "motivational interviewing in the prison context and working with families and children of offenders".

The Singapore Prison Service offers a structured training framework for personnel involved in offender-related work, known as the Development Framework for Offender Rehabilitation Personnel (DORP).

It aims to equip volunteers and aftercare professionals with the relevant skills and qualifications for their work.

Singapore Prison Service is one of eight core members of the CARE Network, which works with more than 100 partners to rehabilitate ex-prisoners. Since CARE Network was formed in 2000, the number of volunteers has grown from about 200 to more than 1,600 in 2013, said Mr Masagos.

To date, all 1,600 volunteers have gone through basic training.

DORP, launched in January this year, has had 339 volunteers and professionals trained in a total of 13 courses. It aims to train up to 1,000 personnel by the end of the year.

Mr Alvin Tan, 39, programme manager at Green Haven halfway house, lauded the plan for more specialised training. He said: "We are working with humans, not machines. We need to have a bag full of tools and skills to work with different individuals."

Last year, 13,944 inmates were released from prison. About one in four falls back to crime after their release.

Repeat offenders remain a concern, even though recidivism rates have been generally stable over the years, said Mr Masagos.

"They comprise more than 80 per cent of the prison population. Many are drug offenders or have drug antecedents. Repeat offenders are also more likely to re-offend and spend a longer time behind bars," he added.

MORE ex-offenders are facing accommodation problems upon their release, said Mr Teo Tze Fang of Singapore Corporation of Rehabilitative Enterprise (SCORE).

"We have seen an increasing number of cases of ex-offenders, usually repeat offenders, being rejected by their families at the last hour prior to their release," said Mr Teo, Score's chief executive officer. "This places a strain on our current shelter programmes, hence we are working with interested partners to increase shelter bed spaces to cater to those in need of interim accommodation."

The programme manager of Green Haven halfway house, Mr Alvin Tan, said it is not unusual to find that ex-offenders' families are not ready to take them back. Former drug addict Derrick Ee, who has been in and out of prison seven times, told The Straits Times that he had voluntarily checked into a halfway house after his recent release from prison in August 2009.

Fortunately for him, Breakthrough Missions gave him shelter. He has since rebuilt his relationship with his wife and family. He was discharged from the halfway house two years ago, but works there full-time. Two months ago, he moved into a new flat with his wife.